1. Field of the Invention
The present invention relates to a lubrication system for automotive transaxles and more particularly to a gutter-like projection provided or an inner wall of a transaxle housing to catch splashed lube oil and introduce it to a transmission input or main shaft journal supporting portion and thenceforth to a lube oil passage formed in the shaft.
2. Description of the Prior Art
Generally, in automotive vehicles equipped with transaxles for a front-engine front-drive system, i.e., F-F vehicles, the overall length of the transmission cannot be as long as that in F-R (front-engine rear-drive) vehicles. For this reason, the input shaft and main shaft of the transmission to be received within the transmission case are arranged in parallel to each other, and between these shafts there is provided a gear train for transmitting motion therebetween. To an open end of the transmission housing (ie, an, entrance portion through which the above shafts and gear train are to be inserted into the transmission case during assembly), there is secured a clutch housing closing the open end, and on this clutch housing one end of each of the above shafts is journaled by bearings. Within the clutch housing, a differential for driving axle shafts (for front wheels) is placed in a manner to form together with the transmission a single unit, i.e., a so-called "transaxle". The differential is operated by a final gearing including a pinion mounted on the main shaft and a ring gear mounted to the differential case. The transaxle is charged with lube oil so that the ring gear is plunged at substantially the lower half part thereof into the oil to splash it when rotated. The clutch housing is formed with a gutter-like projection for catching the lube oil splashed on the housing walls and introducing it to the main shaft journal supporting portion of the clutch housing.
In FIG. 1, there is shown a prior art lubrication system wherein a gutter-like projection, and a boss portion 2 are both integrally formed with the inner wall of the clutch housing. The boss portion 2 receives therewithin the aforementioned bearing for supporting the main shaft journal. The boss portion 2 is formed with a cut 2a for supplying therethrough lube oil caught by the gutter-like projection 1 to the main shaft journal supporting portion and thenceforth to a lube oil passage which will be described hereinlater.
In use, the input shaft and main shaft are subjected to force by which they are urged away from each other since the gear train has an intermeshed portion located between the shafts. The main shaft is also subjected to force resulting from meshing engagement between the above pinion and ring gear urging the main shaft in a direction opposite the first mentioned urging force. For this reason, it is especially necessary for the boss portion 2 to have sufficient rigidity or structural strength. However, since the cut 2a reduces rigidity, the boss portion 2 requires a considerably large thickness "t" to retain a predetermined rigidity and prevent creepage of the boss portion and resulting gear noise. The boss portion 2 with a large thickness inevitably results in increased weight of the clutch housing. Further, the main shaft is formed at the central part thereof with a lube oil passage supplying lube oil to sliding portions of the gears rotatably mounted on the main shaft. The lube oil caught by the gutter-like projection 1 is supplied to the boss portion 2 and thenceforth to the lube oil passage. In this connection, the cut 2a and part of gutter-like projection 1 adjacent the cut are left open at the inner end part thereof to the interior of the transaxle, resulting in lube oil tending to flow out of the intended course along the gutter-like projection and the cut causing the amount of lube oil supplied into the lube oil passage to become smaller and insufficient.